AOI - Computerised inspection of mounted PCBs.

All PCBs assembled (PCBA) in Micro Technics SMT production becomes optically inspected by our computer-based AOI system. 

The AOI-system consists of 15 cameras that takes a high-resolution image of the inspected PCBA.The image of the PCBA is analyzed against a reference board. In analysis, the AOI system will identify the following types of unacceptable deviations:

 

aoi 1

article ul  Wrong components

article ul  Twisted/turned components

article ul  "Tombstoning" (where the component is situated like a tombstone)

article ul  Wrong text on chips (week code, etc.)

article ul  Wrong color shades

 

Some of these mistakes is what is termed "false errors" where AOI system iteratively learns new approved week codes, texts, etc. This means that the system gets better and better the more we use it.
The data and information we get from the AOI system, is used for multiple purposes in our production process:

 

article ul  General debugging

article ul  Statistics analysis for our internal quality control.

article ul  Input to improve the processes in SMT production (eg. attention on specific types of components in the automatic assembly)

article ul  Optimization of the stencils ussed for applying solder paste (eg. reduction of solder paste on specific solder pads)

article ul  Increases our traceability in the production (all PCBAs are scanned and the data from the AOI sysem are stored on our servers).

 

This information will be available to our customers, and they will have the opportunity to optimize their design according to our "Design for manufacturering" philosophy.
 
All PCBAs are registered in our system. Defective boards will be sent to a separate repair station, where the operator will see the specific error on the inspected board on the screen of the repair station. Correction of the defective board will be bery effecient and can be performed in parallel with ongoing production. Once the defective board has been fixed it will once again be checked in AOI system, before it can proceed to the next process in the production.